Air pollution control equipment for a new Hazelwood coke plant will have to remove more nitrogen oxides, sulfur dioxide and other pollutants than the plant's developers had anticipated - an added cost that could help scuttle the controversial project.

The Allegheny County Health Department will require that Sun Co. include a Selective Catalytic Reduction System, or some equivalent technology, in its as-yet-to-be-submitted permit application for a new coke plant on the site of the old LTV coke works.

"Such a technology should be part of Sun's completed application," said Dr. Bruce Dixon, Health Department director. "And if it's not, we would have to have a good reason why not."

The catalytic reduction system was rejected as too expensive last summer in Sun/LTV's original proposal to build a $350 million coke plant. The 300-oven facility would produce up to 1.94 million tons a year and include a cogeneration electric power plant.

Dixon said the county can't require Sun to use a particular pollution control technology, but can require it use "best available control technology" - a technical standard applying to all new installations that emit pollutants.

"We're certainly not going to be satisfied with business as usual in this case," Dixon said. "The company may want to do things in the cheapest way, but we're interested in the safest way."

The Sun/LTV proposal has come under fire from residents of Hazelwood, Greenfield and Squirrel Hill who say they are concerned about the health, property value and economic impacts of a new coke facility in those urban communities.

Use of the catalytic system would significantly reduce the amounts of nitrogen oxides, sulfur dioxide, particulates and lead emitted into the air during the coke-making process, according to a Feb. 10 letter from County Commission Chairman Michael Dawida to the Health Department.

The letter includes a chart that compares emission rates from coke plant proposals by Sun and by Antaeus Energy, which will use the catalytic system at its Neville Island site. It shows that the Sun plant would produce 72 times more nitrogen oxide and 12 times more sulfur dioxide per ton of coke than the Antaeus facility.

Nitrogen oxide is one of the chemicals that combine to form ground-level ozone, the principal component of unhealthy smog.

The Hazelwood area is classified as not meeting federal health standards for ozone and sulfur dioxide.

"I requested that the catalytic reduction of nitrogen oxide be required of Sun, and Dr. Dixon thinks that's appropriate," said Dawida, whose suggestion also has the support of Mayor Murphy, a vocal supporter of the Sun project.

"That catalytic system will make it more difficult for the project to go ahead," Dawida said. "But the idea is not to be difficult, but to be protective of public health. That has to be the first consideration. The location of the facility makes that the primary concern."

Dawida also requested that the Health Department study whether the new plant would produce adverse health effects in the surrounding communities.

Such a study has long been requested by opponents of the Sun proposal, said Mary Lewin, a spokeswoman for Citizens Helping Our Community, a group formed to oppose the plant.

"We are hoping that by doing the health study on what we feel is a dangerous plant and requiring the use of more stringent nitrogen oxide controls, that the two things combined will prevent Sun coke from locating here," Lewin said.

The tougher emission controls and the health study are the latest in a series of setbacks for the Sun Co. proposal.

First, the company wanted to qualify the project for a Federal Synthetic Fuel Tax Credit Program, which would have provided credits of up to $30 for every ton of coke the plant produced. But that program expired in June and wasn't renewed by Congress.

Then the Pittsburgh school board voted against including the Hazelwood site in a Keystone Opportunity Zone, which would have exempted the property from state and local taxes for 12 years.

And the Health Department denied an earlier company request to consider the emissions an "existing source" instead of a "new source," which would have allowed the new plant to emit some pollutants in the same amounts as the plant LTV closed a year ago.

Despite all that and the recent downturn in domestic steel production that could affect the market for coke, Bud Davis, a Sun spokesman, said the company is still pursuing a coking plant in Hazelwood, although other sites outside the area are also under consideration.

Davis said Sun isn't aware of any requirement to include stricter emissions control systems in its application. He said adding a catalytic control system to the facility's exhaust stacks would be "expensive," but declined to cite an exact dollar amount.

"We're waiting until we have a deal with LTV before we submit an application to the county as a new source," Davis said. "Right now our focus is on that business agreement."